The subject that is being defined is how the truth in Heidegger is determined by the relation of the Dasein in opened disposition. The analytics of the Dasein in its architecture, its way of proceeding on the horizon of the thought in Heidegger, substantially uncovers the question of truth. The question is reestablished in an ontological-phenomenological construction of existence on Being and Time and its open need to delve into its etymology. Finally, the investigation defines the way of speech as a foundation of language, which is by nature, the apophantic way of obtaining the truth.